U.S. patent application number 17/051491 was filed with the patent office on 2021-07-22 for method for implementing a measurement system embedded in a component obtained by powder micro-melting.
The applicant listed for this patent is PRES-X S.R.L.. Invention is credited to GIORGIO DE PASQUALE, MAURIZIO ROMEO.
Application Number | 20210220915 17/051491 |
Document ID | / |
Family ID | 1000005520950 |
Filed Date | 2021-07-22 |
United States Patent
Application |
20210220915 |
Kind Code |
A1 |
DE PASQUALE; GIORGIO ; et
al. |
July 22, 2021 |
METHOD FOR IMPLEMENTING A MEASUREMENT SYSTEM EMBEDDED IN A
COMPONENT OBTAINED BY POWDER MICRO-MELTING
Abstract
Method for implementing a measurement system embedded in a
device (D) obtained by powder micro-melting, comprising the steps
of: --manufacturing (100), by using a micro-melting technique, a
covering element (30), --manufacturing (200), by using a
micro-melting technique, a base portion (10) of the device (D)
comprising a work chamber that comprises a sensor seat (15),
interrupting (300) the micro-melting process once the top of the
sidewalls of the base portion (10) of the device (D) has been
reached, opening said work chamber formed by the sensor seat (15),
and exposing the semifinished device (D) to the atmosphere,
--removing (400) the unmelted metal powder that is present within
the sensor seat (15), --positioning (500) the sensor (20) within
the sensor seat (15), --positioning (600) said covering element
(30), previously manufactured during the first step (100), over the
sensor seat (15) containing the sensor (20), and restoring the
inertization of the work chamber and the controlled internal
atmosphere, and--resuming (700) the micro-melting process to form,
on the covering element (30), a closing element (40) by completely
coating the surface with a new layer of powder, which is then
micro-melted, and continuing the normal micro-melting process until
the device (D) is complete.
Inventors: |
DE PASQUALE; GIORGIO;
(OCCHIEPPO INFERIORE, IT) ; ROMEO; MAURIZIO;
(CAMERI, IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PRES-X S.R.L. |
42048 RUBIERA (REGGIO EMILIA) |
|
IT |
|
|
Family ID: |
1000005520950 |
Appl. No.: |
17/051491 |
Filed: |
May 2, 2019 |
PCT Filed: |
May 2, 2019 |
PCT NO: |
PCT/IB2019/053581 |
371 Date: |
October 29, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B33Y 10/00 20141201;
B22F 10/70 20210101; B33Y 80/00 20141201; B33Y 50/02 20141201; B22F
10/30 20210101; B22F 10/20 20210101 |
International
Class: |
B22F 10/20 20210101
B22F010/20; B22F 10/70 20210101 B22F010/70 |
Foreign Application Data
Date |
Code |
Application Number |
May 2, 2018 |
IT |
102018000005012 |
Claims
1-10. (canceled)
11. Method for implementing a measurement system embedded in a
device obtained by powder micro-melting, comprising the steps of:
manufacturing a covering element, by using a micro-melting
technique chosen among SLM (Selective Laser Sintering), EBM
(Electron Beam Melting), and FDM (Fused Deposition Modeling),
manufacturing, by using a micro-melting technique, a base portion
of the device comprising a work chamber that comprises a sensor
seat, interrupting the micro-melting process once the top of the
sidewalls of the base portion of the device has been reached,
opening said work chamber formed by the sensor seat, and exposing
the semi-finished device to the atmosphere, removing the unmelted
metal powder that is present within the sensor seat, positioning
the sensor within the sensor seat, positioning said covering
element, previously manufactured during the first step, over the
sensor seat containing the sensor, and restoring the inertization
of the work chamber and the controlled internal atmosphere, and
resuming the micro-melting process to form, on the covering
element, a closing element by completely coating the surface with a
new layer of powder, which is then micro-melted, and continuing the
normal micro-melting process until the device is complete, wherein
at the end of said step of positioning the sensor within the sensor
seat, a step of applying onto the top surface of the sensor a
thermally insulating element, made of fabric of aramid fiber or
other materials, is carried out in order to protect the sensor
during the subsequent step of resuming the micro-melting
process.
12. Method according to claim 11, wherein, during said step of
manufacturing, by using a micro-melting technique, a device, a
cable seat is also formed, in addition to said sensor seat, for the
passage of a power supply and/or data transmission cable connected
to the sensor.
13. Method according to claim 11, wherein, during said step of
manufacturing, by using a micro-melting technique, a device, the
work chamber is kept under controlled atmosphere by blowing an
inert gas, for the purpose of evacuating the melting fumes and any
combustion residues.
14. Method according to claim 11, wherein, during said step of
removing the unmelted metal powder that is present within the
sensor seat, miniaturized aspirators and/or manual brushes are used
in order to remove the powder that is present on the free top
surface of the base portion of the device.
15. Method according to claim 11, wherein said removed powder is
recovered and recycled.
16. Method according to claim 11, wherein, during said step of
positioning the sensor within the sensor seat, the sensor is
inserted into the sensor seat by either fitting it by friction
against the sidewalls or gluing it to the base of the sensor
seat.
17. Method according to claim 11, wherein, at the end of said step
of positioning said covering element over the sensor seat
containing the sensor, the surfaces of the covering element and of
the base portion of the device are aligned by mechanical or manual
fine positioning.
18. Method according to claim 11, wherein, prior to resuming the
micro-melting process to form a closing element on the covering
element, the exact thickness of the powder layer on the covering
element is restored to obtain a powder layer that is even
throughout its extension, and the passage of the powder deposition
carriage is checked to prevent it from displacing the covering
element of the sensor.
19. Method according to claim 11, wherein said sensor is formed by
multiple sensors for measuring various quantities, wherein said
sensors are positioned at different heights/depths/positions in the
same device within respective sensor seats formed in the base
portion.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to techniques for integrating
sensors within free-form components obtained by powder
micro-melting, which are not subject to common geometric production
constraints.
[0002] The solution according to the present invention allows
avoiding the common problems suffered by the solutions currently
known in the art, which problems relate to high temperatures,
removal of residual powders, and compatibility with currently
available processes and plants.
[0003] More in detail, the invention tackles the problem of
integrating sensors within devices manufactured by powder
micro-melting processes.
[0004] Therefore, the invention proposes a method for embedded
sensorization of free-form components obtained by powder
micro-melting.
BACKGROUND ART
[0005] The techniques currently employed for installing sensors in
devices obtained by powder micro-melting require the use of
conventional interfaces, such as adhesives, threaded connections,
etc.
[0006] Several documents exist which describe known solutions, some
of which will be commented on below. Such comments are useful to
introduce and underline the drawbacks of the solutions that are
available today.
[0007] Document US 2017/0140956 A1, "Single piece ceramic platen"
describes a solution for inserting heating/cooling fluids within
channels of a ceramic component obtained by metal powder
micro-melting. The solution uses a mixture of ceramic powder and a
binding agent. The described solution provides for forming channels
of reduced section, through which such heating/cooling fluids are
introduced into the component. This solution does not envisage the
possibility of installing discrete sensors during the process of
forming the ceramic component.
[0008] Document US 2017/0157857 A1, "Adjusting process parameters
to reduce conglomerated powder", describes a solution for
subjecting the powder to a pre-heating treatment in order to
promote the creation of cavities within a device without the
presence of any undesired solid artifacts in the final component.
In this case as well, the described solution does not envisage the
installation of any sensors in the device, since it only discloses
a powder pre-heating technique.
[0009] Document GB 2538874 A, "Selective Laser Melting", describes
a method of additive manufacturing from a powder bed for
micro-melting of high melting point materials.
[0010] Document WO 2014/166567 A1, "Temperature regulation for a
device for the additive manufacturing of components and
corresponding production method", describes a device for making
components by additive manufacturing based on powder micro-melting,
equipped with a winding for inductive heat generation.
[0011] Article by X. Li, "Embedded sensors in layered
manufacturing", Stanford Univ., 2001 describes the insertion of
unidimensional sensors (e.g. optical fibers) into components
obtained by layer stratification. This document describes a
different production technology, which is not based on powder
micro-melting.
[0012] Article by R. Maier et al., "Embedded fiber optic sensors
within additive layer manufactured components", IEEE Sensors
Journal, 2013 describes the insertion of optical fibers into
components obtained by layer stratification through the use of a
different production technology, which is not based on powder
micro-melting.
[0013] Article by T. Vasilevitsky et al., "Steel-sense: integrating
machine elements with sensors by additive manufacturing", describes
the installation of sensors by means of conventional interfaces to
components obtained by additive manufacturing. It describes an
external, as opposed to embedded, installation of sensors to the
device.
[0014] The solutions currently known do not envisage cooperation or
coexistence of the principle of embedded sensorization within the
component or device with the powder micro-melting technology.
OBJECT AND SUMMARY
[0015] A need is therefore felt for solutions that will allow
overcoming the above-mentioned drawbacks.
[0016] The solution proposed herein allows overcoming the drawbacks
of the prior art techniques by means of a method according to claim
1.
[0017] The main advantage given by the solution described herein
relates to high-performance, high-capacity structural
monitoring.
[0018] The solution described herein allows manufacturing free-form
metal components based on powder micro-melting technology and
equipped with sensors embedded in the component itself.
[0019] In particular, the powder micro-melting manufacturing
processes can be chosen among SLM (Selective Laser Sintering), EBM
(Electron Beam Melting) and FDM (Fused Deposition Modeling).
[0020] Compared to the state of the art, device sensorization is
embedded and invisible, protected against contamination and
interference, positioned in places that are most functionally
effective (because they are close to the source of the quantity to
be measured by the sensor).
[0021] Sensors are currently located, by means of traditional
connections and interfaces (glueing, adhesives and threaded
connections), in external positions, which are vulnerable to
mechanical shocks and noise, and are often far from the source of
the quantity to be measured.
[0022] The innovative character of the production method lies in
the sequence of steps necessary for integrating electronic elements
notwithstanding the constraints inherent in the process (very high
temperatures, presence of metal powder, etc.)
[0023] Some examples of application of the solution proposed herein
are as follows: [0024] support elements for transmission members
(e.g. ball/roller bearings, sliding bearings, recirculating ball
screws, etc.), [0025] fixed or moving/rotary transmission members
(e.g. shafts, toothed wheels, elements of kinematic chains, etc.);
for moving or rotary members, the absence of power wires will make
it possible to carry out monitoring operations with no physical
constraints, [0026] body prostheses, [0027] moulds for melting
polymers/metals, and [0028] structural elements of chassis, frames
and structures of machines and vehicles, also for aeronautical
use.
[0029] A further object of the present invention is to provide a
measurement system embedded in a device obtained by powder
micro-melting, comprising the steps of: [0030] manufacturing, by
using a micro-melting technique, a covering element, [0031]
manufacturing, by using a micro-melting technique, a base portion
of the device comprising a work chamber that comprises a sensor
seat, [0032] interrupting the micro-melting process once the top of
the sidewalls of the base portion of the device is reached, opening
the work chamber formed by the sensor seat, and exposing the
semifinished device to the atmosphere, [0033] removing the unmelted
metal powder that is present within the sensor seat, [0034]
positioning the sensor within the sensor seat, [0035] positioning
the covering element, previously manufactured during the first
step, over the sensor seat containing the sensor, and restoring the
inertization of the work chamber and the controlled internal
atmosphere, and [0036] resuming the micro-melting process to form,
on the covering element, a closing element by completely coating
the surface with a new layer of powder, which is then micro-melted,
and continuing the normal micro-melting process until the device is
complete.
[0037] In several embodiments, during the step of manufacturing a
device by using a micro-melting technique, a cable seat is also
formed, in addition to the sensor seat, for the passage of a power
supply and/or data transmission cable connected to the sensor.
[0038] In several embodiments, during the step of manufacturing a
device by using a micro-melting technique, the work chamber is kept
under controlled atmosphere by blowing an inert gas, for the
purpose of evacuating the melting fumes and any combustion
residues.
[0039] In several embodiments, in particular, during the step of
removing the unmelted metal powder that is present within the
sensor seat, miniaturized aspirators and/or manual brushes are used
in order to remove the powder that is present on the free top
surface of the base portion of the device.
[0040] In the preferred embodiments, the removed powder is
recovered and recycled. Preferably, during the step of positioning
the sensor within the sensor seat, the sensor is inserted into the
sensor seat by either fitting it by friction against the sidewalls
or glueing it to the base of the sensor seat.
[0041] In several embodiments, at the end of the step of
positioning the sensor within the sensor seat, a step of applying
onto the top surface of the sensor a thermally insulating element,
made of fabric of aramid fiber or other materials, is carried out
in order to protect the sensor during the next step of resuming the
micro-melting process.
[0042] Still with reference to the preferred embodiments, at the
end of the step of positioning the covering element over the sensor
seat containing the sensor, the surfaces of the covering element
and of the base portion of the device are aligned by mechanical or
manual fine positioning.
[0043] Finally, in several embodiments, prior to resuming the
micro-melting process to form a closing element on the covering
element, the exact thickness of the powder layer on the covering
element is restored to obtain a powder layer that is even
throughout its extension, and the passage of the powder deposition
carriage is checked to prevent it from displacing the covering
element of the sensor.
[0044] Preferably, the sensor is formed by multiple sensors for
measuring several quantities, wherein the sensors are positioned at
different heights/depths/positions in the same device within
respective sensor seats.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045] Further features and advantages of the invention will be
illustrated in the following detailed description, which is
provided merely by way of non-limiting example with reference to
the annexed drawings, wherein:
[0046] FIG. 1 is an exploded view of one example of embodiment of a
device according to the present invention, and
[0047] FIG. 2 is a sectional view of the device of FIG. 1.
DETAILED DESCRIPTION
[0048] The following description will illustrate various specific
details useful for a deep understanding of some examples of one or
more embodiments. The embodiments may be implemented without one or
more of such specific details or with other methods, components,
materials, etc. In other cases, some known structures, materials or
operations will not be shown or described in detail in order to
avoid overshadowing various aspects of the embodiments. Any
reference to "an embodiment" in this description will indicate that
a particular configuration, structure or feature is comprised in at
least one embodiment. Therefore, the phrase "in an embodiment" and
other similar phrases, which may be present in different parts of
this description, will not necessarily be all related to the same
embodiment. Furthermore, any particular configuration, structure or
feature may be combined in one or more embodiments as deemed
appropriate.
[0049] The references below are therefore used only for
simplicity's sake, and do not limit the protection scope or
extension of the various embodiments.
[0050] Powder micro-melting processes are based on localized
concentration of a heat source (e.g. a laser beam or an electron
beam) capable of causing a state change in the metal with a high
degree of dimensional detail.
[0051] The initial metal powder, disposed on a bed, undergoes a
process of melting and subsequent solidification in successive
superimposed layers, until the desired final geometry is
obtained.
[0052] Suitable systems currently available on the market can
manage the entire process, from supplying and moving the powder to
controlling the atmosphere, the heat source and the handling of the
workpiece being manufactured.
[0053] Powder micro-melting technologies are dedicated to metal
materials (typically aluminium or titanium alloys, steel and
nickel-based materials).
[0054] Powder micro-melting technologies have become increasingly
widespread in the last decade due to the development of the
production chain connected to "additive manufacturing", including
dedicated design systems (software for topological optimization and
machine setup), refined production and powder-control techniques,
stable processes and machines, suitably tuned post-production
thermal treatments, and increased final users' awareness of the new
technology.
[0055] The main advantages associated with components obtained by
powder micro-melting certainly include the possibility of
manufacturing components having high geometrical complexity
(free-form components) with less or no process complications.
[0056] This feature meets requirements in terms or weight
reduction, local strain control, local control of forced cooling,
increased versatility of moulds and prototypes.
[0057] The present invention relates to a method for manufacturing
components, the execution of which is associated with a
micro-melting process. The solution described herein aims at
improving the performance of the manufactured components by
providing them with embedded sensors.
[0058] The solution considered herein comes from a deep knowledge
of the process and of the management and experimentation of the
same, which is the result of years of experience in the industrial
field.
[0059] As already anticipated, integration of discrete sensors
within the device or component during the manufacturing thereof by
powder micro-melting is currently impossible because of problems
encountered in the process, such as: [0060] difficulty in
interacting with process automation and continuity, which are
necessary to achieve stratification of the melted powder, and
difficulty in ensuring structural continuity and good mechanical
properties of the device in the event of an interruption of the
process; [0061] higher temperature due to the micro-melting process
and the subsequent heat treatment, which destroys electronic
components, such as sensors; and [0062] difficulty in controlling
unmelted regions in the component (e.g. in correspondence with
sensor seats) because of the presence therein of residual metal
powder that is difficult to remove.
[0063] The processes suitable for supporting the solution described
herein, appropriately modified, include: [0064] SLM (selective
laser sintering), [0065] EBM (electron beam melting), and [0066]
FDM (fused deposition modeling).
[0067] The method for manufacturing components according to the
present invention is based on the following steps, described herein
merely by way of example.
[0068] FIG. 1 is an exploded view of one possible embodiment of a
device D made in accordance with the method of the present
invention.
[0069] In particular, the device D comprises a base portion 10 made
from micro-melted material. Inside such base portion 10 a chamber
is formed, which creates a sensor seat 15 shaped for receiving
therein a sensor 20 having the same basic geometry as the
respective sensor seat 15.
[0070] More in detail, the sensor seat 15 may have a circular,
square or any other shape, so as to be able to house a sensor 20,
which may have a matching shape or a shape that allows it to be
received within the sensor seat 15. The sensor seat 15 comprises a
base portion 15a, a back wall 15b and two sidewalls 15c.
[0071] Typically, the dimensions of the sensor seat 15 are such as
to allow the sensor 20 to be inserted therein without
interference.
[0072] As shown more clearly in FIG. 2, the sensor 20 is housed
within the sensor seat 15 with some clearance.
[0073] In several embodiments, the sensor 20 is equipped with a
power and signal transmission cable 25 that is received into a
corresponding cable seat 18 formed in the base portion 10 adjacent
to the sensor seat 15. The cable 25 is also received in the
corresponding cable seat 18 with some clearance.
[0074] Still with reference to FIG. 1, there is a covering element
30 adapted to close the chamber formed by the sensor seat 15 and
the cable seat 18 in the base portion 10. In particular, the
covering element 30 comprises a larger first portion 30a, adapted
to cover the sensor seat 15, and a smaller lateral portion 30b,
adapted to cover the cable seat 18.
[0075] The nominal dimensions of the covering element 30 are not
identical to those of the sensor seat 15 and cable seat 18, but are
defined after testing campaigns for evaluating contraction rates
(dimensional shrinkage rates) and geometrical tolerances in order
to detect differences as small as one tenth of a millimeter.
[0076] The sidewalls 30c1 and 30c2 of the covering element 30 are
not vertical, but tilted by a variable angle of 5.degree. to
30.degree. for the purpose of ensuring correct insertion and stable
positioning thereof into the respective sensor seat 15 and cable
seat 18. The walls 15c of the sensor seat 15 and the walls 18c of
the cable seat 18 are tilted by the same angle, except for a
suitable installation gap.
[0077] Finally, a closing element 40 made of micro-melted material
seals the device 10. The granulometry of the powders may vary,
depending on whether a laser beam or electron beam melting process
is carried out, from 12 .mu.m to 105 .mu.m, with a suitable
Gaussian curve identifying the distribution thereof with a specific
range for each system and brand.
[0078] The percent majority of the granulometry must be centered on
the mean value of the respective Gaussian curve.
[0079] One of the parameters that are most representative of a
perfect compliance of powders for additive manufacturing is their
"flowability", i.e. the value that identifies how easily the powder
can run and be spread on the melting plane.
[0080] The higher the "flowability" is, the better the result
obtained, thus ensuring perfect spreading over the entire melting
plane, with no uncovered areas.
[0081] The same powder (raw material) must be carefully monitored
as regards the value of the humidity contained therein.
[0082] In fact, humidity is second in the list of parameters that
may more affect the quality of the final melting process.
[0083] As aforementioned, the covering element 30 may comprise one
or more lateral portions 30b that can be used for covering the
cable seat 18 adapted to receive the power and signal transmission
cable 25 of the sensor 20. Also this lateral portion 30b is
provided with sidewalls 30c2 within tolerance, tilted similarly to
the main covering element 30a.
[0084] The following will describe the steps of the method
according to the present invention. In a first step 100, the
covering element 30 is manufactured.
[0085] In a second step 200, the device D is manufactured. In
particular, the device D is manufactured in accordance with an
engineering drawing comprising the base portion 10, the chamber
that will form the sensor seat 15 and, possibly, one or more cable
seats 18 for the passage of the power and/or data transmission
cable 25.
[0086] Micro-melting goes on in successive superimposed layers, as
is typical of SLM processes. More in detail, micro-melting
processes utilize a laser speed of 1500 mm/sec to 4000 mm/sec.
[0087] Typically, micro-melting processes utilize a laser power of
70 W to 1 KW. In several embodiments, the hatching distance is
selected between -0.2 mm and +0.1 mm. In several embodiments, the
plate is heated to 150.degree. C., when laser technology is used,
or the layer is pre-heated to 740.degree. C. to 1300.degree. C.,
when EBM technology is used.
[0088] Preferably, in several embodiments the electron beam
scanning speed is selected between 8000 mm/sec and 22000
mm/sec.
[0089] Finally, in several embodiments the power value is selected
between 1 KW and 8 KW. In a next step 300, the micro-melting
process is interrupted when the top of the sidewalls of the device
10 has been reached.
[0090] Subsequently, the work chamber, formed by the sensor seat 15
and the cable seat 18, is opened and the semifinished product is
exposed to the atmosphere, which may result in undesired surface
oxidation processes. In particular, during the micro-melting
process, the process chamber is maintained under controlled
atmosphere by blowing an inert gas, such as ARGON, in order to
evacuate the melting fumes and any combustion residues. In case of
an EBM process, the melting chamber and the associated electron gun
are placed under a very high degree of vacuum
(10.sup.-5/10.sup.-7). In this way, it is not necessary to inert
the process chamber, since it is already free from oxygen, i.e. in
a non-oxidative or fumeless environment.
[0091] In a subsequent step 400, the unmelted metal powder that is
present in the sensor seat 15 and in the cable seat 18, if any,
adapted to receive the cable 25, is manually removed. In several
embodiments, the unmelted metal powder is removed by means of
miniaturized aspirators and/or manual brushes. In particular, the
powder that is present on the free top surface of the device D, in
particular of the base portion 10, is removed. The removed powder,
which has undergone no damage, is then recovered and recycled. In a
further step 500, the sensor 20 is positioned within the sensor
seat 15, and the power cable 25, if any, is positioned within the
cable seat 18.
[0092] The sensor 20 is inserted into the sensor seat 15 in either
one of the following most appropriate ways: fitting by friction
against the sidewalls 15c or glueing to the base 15a of the sensor
seat 15.
[0093] Furthermore, in several embodiments a thermally insulating
element, made of fabric of aramid fiber or other materials, is
applied onto the top surface of the sensor 20 in order to protect
the sensor 20 during the subsequent resumption of the micro-melting
process. Any portions of the cable 25 protruding from the base
portion 10 of the device D are protected by means of temporary
coverings, e.g. coverings consisting of bags, and buried into the
powder that is present at the sides of the base portion 10 of the
device D.
[0094] In a further step 600, the covering element 30 previously
made at step 100 is positioned over the sensor seat 15 containing
the sensor 20 and the cable seat 18, if any, containing the cable
25.
[0095] Subsequently, the surfaces of the covering element 30 and
base portion 10 of the device D are aligned, possibly by mechanical
or manual fine positioning. The inertization of the process chamber
and the controlled atmosphere are then restored prior to resuming
the additive manufacturing process.
[0096] In a last step 700, the micro-melting process is resumed to
completely coat the surface above the covering element 30 with a
new layer of powder, which is then micro-melted. This step is
particularly delicate because it is necessary to restore the exact
thickness of the powder layer on top of the previously inserted
cover, and the whole powder layer must be perfectly even again,
throughout its extension. It is also necessary to ensure that the
passage of the powder deposition carriage will not move or displace
the covering element 30 of the sensor 20 just positioned. The
normal process continues until the device D is complete. At the end
of this last step, the closing element 40 will have been fully
manufactured.
[0097] In order to obtain the necessary structural continuity, the
time required for the execution of steps 300-700 must be short
enough to prevent the part from cooling too quickly or too long,
which may result in thermal and geometrical shrinkage of the base
portion 10 of the melted device D beneath the interruption
layer.
[0098] Should the step of inserting the covering element 30 and
restoring the powder layer last too long, there could be a risk
that the same covering element 30 might no longer "fit" inside the
respective seat 15,18.
[0099] In order to carry out the above-listed steps, it is
necessary to interact with the automated production process and
make due changes to the settings and controls included in the
systems currently available on the market.
[0100] The manipulation of the base portion 10 of the device D
while making and handling electric parts also requires interaction
with the micro-melting chamber, the controlled atmosphere therein
(to be restored after installation), and the powder bed.
[0101] Such modifications can only be made by skilled and suitably
trained personnel, in that they will alter the optimal operating
and safety conditions of the entire process and system. Particular
care and attention should also be paid to the welding/melting of
the first layer of powder after the insertion of the covering
element 30, so as to not leave or create any incompletely melted
regions that might jeopardize the integrity of the sensor 20 and
also the proper operation of the additive melting system.
[0102] After the process, the thermal annealing treatment of the
device D must be calibrated to include a suitable number of
heating-cooling steps, such that the integrity of the electronic
parts (sensors and any cables and connectors) will not be
compromised. Therefore, traditional thermal processes are
re-modulated through a sequence of heating-cooling steps that suit
the thermal resistance of the electronic components. The sensors 20
employed are selected among those capable to resist micro-melting
and post-process thermal annealing treatment temperatures.
[0103] Power/data transmission cables 25 are heat-shielded (e.g. by
means of silicone shields or the like).
[0104] Simple sensors may be replaced with complex circuit elements
consisting of measurement elements (sensors), wireless transmission
elements, microcontroller elements and, possibly, a rechargeable
battery, or micro-generators (integrated energy harvesters, e.g. of
the piezoelectric or magnetic-inductive type).
[0105] In this case, the electronic elements of the sensor 20 will
be completely internal to the component or device D, without the
presence of any cable 25.
[0106] The additive technology permits inserting not only a single
sensor 20, but multiple sensors 20 for measuring various quantities
at different heights/depths/positions into the same sensor-carrying
device.
[0107] The typology of the electronic components must be
appropriately identified to meet the minimum requirements of the
modified micro-melting process in terms of thermal-mechanical
resistance.
[0108] Some examples of application of the solution described
herein are as follows: [0109] support elements for transmission
members (e.g. ball/roller bearings, sliding bearings, recirculating
ball screws, etc.); [0110] fixed or moving/rotary transmission
members (e.g. shafts, toothed wheels, elements of kinematic chains,
etc.); for moving or rotary members, the absence of power wires
will make it possible to carry out monitoring operations with no
physical constraints; [0111] body prostheses; [0112] moulds for
melting polymers/metals; [0113] structural elements of chassis,
frames and structures of machines and vehicles, also for
aeronautical use; and [0114] calipers for vehicular braking
systems.
[0115] The solution of the invention is innovative and permits the
implementation of a practice that until now could not be used
because of technological constraints of the plants and physical
constraints of the process itself.
[0116] The component or device D obtained by means of a process
according to the invention can be equipped with embedded sensors
which are invisible, bulkless, insensitive to contamination and to
the outside environment, and capable of sensing physical quantities
in wired or wireless mode.
[0117] Such performance will add to the already known advantages of
free-form components, which are not subject to the usual
geometrical constraints of technological fabrication processes.
[0118] The main advantages that can be achieved are the following:
[0119] monitoring of mechanical structures by means of sensors
embedded into the components, resulting in better reliability
(insensitiveness to shocks and interaction with the environment),
[0120] higher measurement precision due to the vicinity to the
point to be monitored, and [0121] application of multiple
measurement points within small volumes (e.g. bearing seats), which
would not be possible in case of external installation or
installation through traditional drilling.
[0122] Of course, without prejudice to the principle of the
invention, the forms of embodiment and the implementation details
may be extensively varied from those described and illustrated
herein merely by way of non-limiting example, without however
departing from the protection scope of the present invention as set
out in the appended claims.
* * * * *